1. Field of the Invention
The present invention relates to a portable memory assembly including an IC memory for use in processing and/or storing data.
2. Description of the Related Art
Portable memory assemblies comprise a flat memory assembly, such as a card-shaped memory or a coin-shaped memory, having a structure in which one main surface of a wiring board has an IC memory chip for use in processing and/or storing data mounted thereto, and the other main surface of the wiring board has a plurality of connecting terminals connected to external terminals of a data processing device outside the memory assembly when the memory assembly receives and sends data from and to the data processing device. The connecting terminals are connected to the IC memory chip through electrically conductive through-holes in the wiring board and through wiring patterns formed on the one main surface of the wiring board.
In this memory assembly, a package of vinyl chloride covers the one main surface of the wiring board and the IC memory chip and the other main surface of the wiring board directly constitutes the exterior surface of the memory assembly so that the connecting terminals extend outside of the memory assembly. Thus, friction between the exterior surface of the memory assembly and clothes of a user of the memory assembly may charge the exterior surface of the memory assembly with static electricity, so that the IC memory chip is charged with the electricity via the connecting terminals, the conductive through-holes and the wiring patterns. When a conductor such as human body contacts part of the connecting terminals, the IC memory chip may discharge the electricity via the part of the connecting terminals, the conductive through-hole and the wiring patterns. During the discharge, a relatively high current may pass through part of wiring patterns of a metal such as aluminum in the IC memory chip to heat, melt and break the part of the wiring patterns in the IC memory chip.